US12062499B2 - Film capacitor element and film capacitor - Google Patents

Film capacitor element and film capacitor Download PDF

Info

Publication number
US12062499B2
US12062499B2 US17/785,258 US202017785258A US12062499B2 US 12062499 B2 US12062499 B2 US 12062499B2 US 202017785258 A US202017785258 A US 202017785258A US 12062499 B2 US12062499 B2 US 12062499B2
Authority
US
United States
Prior art keywords
film
electrode
films
dielectric
film capacitor
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active, expires
Application number
US17/785,258
Other versions
US20230021057A1 (en
Inventor
Yuki SENOO
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Kyocera Corp
Original Assignee
Kyocera Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Kyocera Corp filed Critical Kyocera Corp
Assigned to KYOCERA CORPORATION reassignment KYOCERA CORPORATION ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: SENOO, YUKI
Publication of US20230021057A1 publication Critical patent/US20230021057A1/en
Application granted granted Critical
Publication of US12062499B2 publication Critical patent/US12062499B2/en
Active legal-status Critical Current
Adjusted expiration legal-status Critical

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G4/00—Fixed capacitors; Processes of their manufacture
    • H01G4/002—Details
    • H01G4/005—Electrodes
    • H01G4/012—Form of non-self-supporting electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G4/00—Fixed capacitors; Processes of their manufacture
    • H01G4/002—Details
    • H01G4/018—Dielectrics
    • H01G4/06—Solid dielectrics
    • H01G4/14—Organic dielectrics
    • H01G4/18—Organic dielectrics of synthetic material, e.g. derivatives of cellulose
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G4/00—Fixed capacitors; Processes of their manufacture
    • H01G4/002—Details
    • H01G4/224—Housing; Encapsulation
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G4/00—Fixed capacitors; Processes of their manufacture
    • H01G4/30—Stacked capacitors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G4/00—Fixed capacitors; Processes of their manufacture
    • H01G4/32—Wound capacitors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G4/00—Fixed capacitors; Processes of their manufacture
    • H01G4/002—Details
    • H01G4/018—Dielectrics
    • H01G4/02—Gas or vapour dielectrics

Definitions

  • the present disclosure relates to a film capacitor element and a film capacitor including the film capacitor element.
  • Patent Literature 1 A known technique is described in, for example, Patent Literature 1.
  • a film capacitor element includes a body including a plurality of dielectric films, a plurality of first electrode films, and a plurality of second electrode films being stacked on one another or being wound together, a first external electrode at one end of the body and electrically connected to the plurality of first electrode films, and a second external electrode at another end of the body and electrically connected to the plurality of second electrode films.
  • the body includes a capacitance portion in which each of the plurality of first electrode films faces a corresponding second electrode film of the plurality of second electrode films with a corresponding dielectric film of the plurality of dielectric films in between, and the capacitance portion includes spaces each between a corresponding dielectric film of the plurality of dielectric films and a corresponding first electrode film of the plurality of first electrode films or between a corresponding dielectric film of the plurality of dielectric films and a corresponding second electrode film of the plurality of second electrode films.
  • a film capacitor according to one aspect of the present disclosure includes the film capacitor element, a housing accommodating the film capacitor element, and a sealant sealing the film capacitor element accommodated in the housing.
  • FIG. 1 is a schematic cross-sectional view of a film capacitor element according to one embodiment of the present disclosure, taken along one plane in a first direction X.
  • FIG. 2 A is a diagram describing a procedure for expanding air and other gases remaining in film electrodes.
  • FIG. 2 B is a diagram describing a procedure for vaporizing and expanding a solvent remaining in the film electrodes.
  • FIG. 3 is a diagram of the film capacitor element encapsulated with a resin.
  • FIG. 4 is a schematic diagram describing the pressure from the resin encapsulation applied to the film capacitor element.
  • FIG. 5 is a schematic cross-sectional view of a film capacitor according to one embodiment of the present disclosure.
  • a film capacitor element and a film capacitor including a wound body with at least a pair of dielectric films each including an electrode film on the surface wound together, and a pair of metal-sprayed electrodes on both ends of the wound body are described.
  • the wound body includes an active portion in which electrode films in the pair of dielectric films overlap each other, and the diameter of the active portion is greater than the diameter of each metal-sprayed electrode in the cross section perpendicular to the winding axis of the wound body to reduce the volume ratio of each metal-sprayed electrode.
  • the resultant film capacitor can have a smaller size and larger capacity.
  • FIG. 1 is a schematic cross-sectional view of a film capacitor element according to one embodiment of the present disclosure, taken along one plane in a first direction X.
  • a film capacitor element 1 includes a body 20 including multiple dielectric films 2 a and 2 b and film electrodes 6 including electrode films 4 a and 4 b on the surfaces of the dielectric films 2 a and 2 b stacked on one another or wound together.
  • the film capacitor element 1 also includes a pair of external electrodes 3 a and 3 b on both ends of the body 20 in the first direction X connected to the electrode films 4 a and 4 b in the multiple film electrodes 6 to form a capacitance portion 20 c (active portion).
  • the capacitance portion 20 c is at the middle between the ends of the body 20 in the first direction X.
  • the body 20 has spaces S between the film electrodes 6 .
  • the dielectric films 2 a and 2 b are plastically deformed with the spaces S in the stacking direction.
  • the width of each space S or specifically, the distance in the stacking direction between adjacent film electrodes 6 across the space S, is, for example, at least 0.5 ⁇ m.
  • the width of each space S may be, for example, one or more times the thickness of the dielectric film 2 a or 2 b , or two or more times the thickness of the dielectric film 2 a or 2 b .
  • Each film electrode 6 has multiple microscopic recesses 7 on its surface.
  • Each recess 7 may be replaced by a hole that is circular, oval, polygonal, or star-shaped in a plan view, or a groove that is linear, arc-shaped, or dendritic in a plan view.
  • Each recess 7 may also be replaced by two or more holes or grooves connected together.
  • the depth of each recess 7 may be, for example, 10 nm or greater and less than or equal to half the thickness of the dielectric film 2 a or 2 b .
  • the diameter of the recess 7 in a plan view may be, for example, from 10 nm to 2 ⁇ m inclusive.
  • the width of the recess 7 in a plan view may be, for example, from 10 nm to 2 ⁇ m inclusive, and the length may be, for example, 200 ⁇ m or less.
  • the density of the recesses 7 may be, for example, 1 to 1000 recesses/mm 2 or less.
  • the recesses 7 have the ratio of the diameter to the depth of the hole (diameter/depth) or the ratio of the width to the depth of the groove (width/depth) being 3 or less.
  • the dielectric film 2 a or 2 b may be simply referred to as the dielectric film 2 .
  • the electrode film 4 a or 4 b may be simply referred to as the electrode film 4 .
  • the film capacitor element 1 may be fabricated with the procedure described below.
  • the dielectric film 2 is prepared first.
  • the dielectric film 2 is obtained by, for example, preparing a resin solution by dissolving an insulating resin in a solvent, applying the resin solution on the surface of a base film of, for example, polyethylene terephthalate (PET) in a sheet, and drying the sheet to volatilize the solvent.
  • PET polyethylene terephthalate
  • the sheet may be applied with a method selected as appropriate from known film deposition methods including doctor blading, die coating, and knife coating.
  • Examples of the solvent used for the sheet include methanol, isopropanol, n-butanol, ethylene glycol, ethylene glycol monopropyl ether, methyl ethyl ketone, methyl isobutyl ketone, xylene, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, dimethylacetamide, cyclohexane, and an organic solvent containing a mixture of two or more solvents selected from the above solvents.
  • the dielectric film 2 can also be formed by stretching a film of resin formed by melt extrusion.
  • the dielectric film 2 may have the thickness of, for example, 5 ⁇ m or less, or specifically the thickness of 0.5 to 2 ⁇ m.
  • the insulating resin for the dielectric film 2 examples include polypropylene (PP), PET, polyphenylene sulfide (PPS), polyethylene naphthalate (PEN), polyarylate (PAR), polyphenylene ether (PPE), polyetherimide (PEI), and cycloolefin polymers (COPs).
  • the insulating resin may specifically be COPs having a high insulation breakdown voltage.
  • the dielectric film 2 may contain the insulating resin selected from the above examples alone or may include other materials.
  • the materials that may be included in the dielectric film 2 other than the resin include, for example, the above organic solvent and an inorganic filler.
  • the inorganic filler include an inorganic oxide such as alumina, titanium oxide, or silicon dioxide, an inorganic nitride such as silicon nitride, and glass.
  • a material with a high relative dielectric constant such as a composite oxide having a perovskite structure may be used as an inorganic filler.
  • the dielectric film 2 has a higher relative dielectric constant across the film.
  • the film capacitor using this dielectric film 2 can have a smaller size.
  • the inorganic filler may be surface-treated by, for example, silane coupling treatment or titanate coupling treatment.
  • FIG. 2 A is a diagram describing a procedure for expanding air and other gases remaining in the film electrodes 6 .
  • the electrode films 4 are eliminated for ease of illustration.
  • the film capacitor element 1 including the film electrodes 6 with the multiple microscopic recesses 7 being stacked may be, for example, heated to expand air remaining in the microscopic recesses 7 .
  • the expanded air enters between the film electrodes 6 , forming the spaces S between the film electrodes 6 .
  • the dielectric film 2 is plastically deformed with the spaces S being formed. When the film capacitor element 1 is cooled, the spaces S remain between the film electrodes 6 .
  • the film capacitor element 1 including the film electrodes 6 with the multiple microscopic recesses 7 being stacked may be accommodated in a container, and the container accommodating the film capacitor element 1 may be evacuated to expand the air in the microscopic recesses 7 on the film electrode 6 .
  • the expanded air enters between the film electrodes 6 , forming the spaces S between the film electrodes 6 .
  • the dielectric film 2 is plastically deformed with the spaces S being formed.
  • the container accommodating the film capacitor element 1 is under the atmospheric pressure, the spaces S remain between the film electrodes 6 .
  • the film capacitor element 1 including the film electrodes 6 with the multiple microscopic recesses 7 being stacked may be accommodated in a container.
  • the container accommodating the film capacitor element 1 may be evacuated, and the film capacitor element 1 may be heated to expand the air in the recesses 7 on the film electrode 6 more easily.
  • FIG. 2 B is a diagram describing a procedure for vaporizing a solvent remaining in the film electrodes 6 .
  • the electrode films 4 are eliminated for ease of illustration.
  • the film capacitor element 1 including the film electrodes 6 being stacked may be, for example, heated to vaporize the solvent remaining between the film electrodes 6 .
  • the vaporized solvent enters between the film electrodes 6 to form the spaces S between the film electrodes 6 .
  • the dielectric film 2 is plastically deformed with the spaces S being formed. When the film capacitor element 1 is cooled, the spaces S remain between the film electrodes 6 .
  • FIG. 3 is a diagram of the film capacitor element 1 encapsulated with a resin.
  • L max ⁇ 1 m is the maximum thickness difference
  • (L max ⁇ 1 m )/1 m ⁇ 100 is the maximum expansion rate (%) in the stacking direction, where L max is the dimension of the expanded body 20 in the stacking direction, and 1 m is the dimension of the external electrode 3 a or 3 b in the stacking direction.
  • the maximum thickness difference and the maximum expansion rate in the stacking direction are both greater than 0.
  • the maximum thickness difference may be, for example, greater than or equal to the thickness of the dielectric film 2 or greater than or equal to 0.5 ⁇ m.
  • the maximum expansion rate in the stacking direction may be 100% or less, 50% or less, or specifically 25% or less.
  • Terminals 5 are connected to the external electrodes 3 a and 3 b.
  • FIG. 4 is a schematic diagram describing the pressure from the resin encapsulation applied to the film capacitor element 1 .
  • the dielectric film 2 in each layer is plastically deformed with the capacitance portion 20 c between the pair of external electrodes 3 a and 3 b expanding in the stacking direction and the spaces S between the film electrodes 6 in the layers.
  • the pressure applied to the capacitance portion 20 c in the stacking direction is reduced with air or other gases in the spaces S between the film electrodes 6 in the layers.
  • the gases in the spaces S may flow from gaps around the external electrodes 3 a and 3 b into the spaces S in the other layers. This further reduces the pressure applied to the capacitance portion 20 c.
  • This structure reduces the likelihood of high pressure being applied to the capacitance portion 20 c in the stacking direction and reduces thermal damage to the film electrodes 6 due to contact between the film electrodes 6 under high pressure and thus reduces breaks from any short circuit.
  • the spaces S may be formed at least partially in the stacking direction of the body 20 .
  • the spaces S may extend over both ends of the body 20 in the first direction X, or may extend partially between the two ends.
  • FIG. 5 is a schematic cross-sectional view of a film capacitor according to one embodiment.
  • a film capacitor 100 includes the film capacitor element 1 according to the above embodiment, a housing 10 accommodating the film capacitor element 1 , and a sealant 9 sealing the film capacitor element 1 accommodated in the housing 10 .
  • the sealant 9 is, for example, a resin.
  • the film capacitor 100 can be less susceptible to breaks due to a short circuit and is highly reliable.
  • the film capacitor element is not limited to the film capacitor element 1 described in FIGS. 1 to 4 , but may be any other film capacitor element.
  • the electrode films 4 a and 4 b and the dielectric films 2 a and 2 b without being joined together may be stacked on one another or wound together, without the electrode films 4 a and 4 b being formed on the dielectric films 2 a and 2 b .
  • the film electrode 6 including the dielectric film 2 a with an electrode film 4 a on one surface of the dielectric film 2 a and an electrode film 4 b on the other surface of the dielectric film 2 a , and the dielectric film 2 b with no electrode films 4 a and 4 b may be stacked on one another or wound together.
  • a film capacitor element includes a body including a plurality of dielectric films, a plurality of first electrode films, and a plurality of second electrode films being stacked on one another or being wound together, a first external electrode at one end of the body and electrically connected to the plurality of first electrode films, and a second external electrode at another end of the body and electrically connected to the plurality of second electrode films.
  • the body includes a capacitance portion in which each of the plurality of first electrode films faces a corresponding second electrode film of the plurality of second electrode films with a corresponding dielectric film of the plurality of dielectric films in between, and the capacitance portion includes spaces each between a corresponding dielectric film of the plurality of dielectric films and a corresponding first electrode film of the plurality of first electrode films or between a corresponding dielectric film of the plurality of dielectric films and a corresponding second electrode film of the plurality of second electrode films.
  • a film capacitor according to one aspect of the present disclosure includes the film capacitor element, a housing accommodating the film capacitor element, and a sealant sealing the film capacitor element accommodated in the housing.
  • the film capacitor element and the film capacitor according to the embodiments of the present disclosure can reduce breaks due to a short circuit and are highly reliable.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Fixed Capacitors And Capacitor Manufacturing Machines (AREA)

Abstract

A body includes dielectric films, first electrode films, and second electrode films being stacked on one another or being wound together. A first external electrode is at one end of the body and electrically connected to the first electrode films. A second external electrode is at another end of the body and electrically connected to the second electrode films. The body includes a capacitance portion in which each of the first electrode films faces a corresponding second electrode film of the second electrode films with a corresponding dielectric film of the dielectric films in between, and the capacitance portion includes spaces each between a corresponding dielectric film of the dielectric films and a corresponding first electrode film of the first electrode films or between a corresponding dielectric film of the dielectric films and a corresponding second electrode film of the second electrode films.

Description

FIELD
The present disclosure relates to a film capacitor element and a film capacitor including the film capacitor element.
BACKGROUND
A known technique is described in, for example, Patent Literature 1.
CITATION LIST Patent Literature
  • Patent Literature 1: Japanese Unexamined Patent Application Publication No. 2015-211071
BRIEF SUMMARY
A film capacitor element according to one aspect of the present disclosure includes a body including a plurality of dielectric films, a plurality of first electrode films, and a plurality of second electrode films being stacked on one another or being wound together, a first external electrode at one end of the body and electrically connected to the plurality of first electrode films, and a second external electrode at another end of the body and electrically connected to the plurality of second electrode films. The body includes a capacitance portion in which each of the plurality of first electrode films faces a corresponding second electrode film of the plurality of second electrode films with a corresponding dielectric film of the plurality of dielectric films in between, and the capacitance portion includes spaces each between a corresponding dielectric film of the plurality of dielectric films and a corresponding first electrode film of the plurality of first electrode films or between a corresponding dielectric film of the plurality of dielectric films and a corresponding second electrode film of the plurality of second electrode films.
A film capacitor according to one aspect of the present disclosure includes the film capacitor element, a housing accommodating the film capacitor element, and a sealant sealing the film capacitor element accommodated in the housing.
BRIEF DESCRIPTION OF DRAWINGS
The objects, features, and advantages of the present disclosure will be more apparent from the detailed description and the drawings below.
FIG. 1 is a schematic cross-sectional view of a film capacitor element according to one embodiment of the present disclosure, taken along one plane in a first direction X.
FIG. 2A is a diagram describing a procedure for expanding air and other gases remaining in film electrodes.
FIG. 2B is a diagram describing a procedure for vaporizing and expanding a solvent remaining in the film electrodes.
FIG. 3 is a diagram of the film capacitor element encapsulated with a resin.
FIG. 4 is a schematic diagram describing the pressure from the resin encapsulation applied to the film capacitor element.
FIG. 5 is a schematic cross-sectional view of a film capacitor according to one embodiment of the present disclosure.
 DETAILED DESCRIPTION
As the structure that forms the basis of the present disclosure, a film capacitor element and a film capacitor including a wound body with at least a pair of dielectric films each including an electrode film on the surface wound together, and a pair of metal-sprayed electrodes on both ends of the wound body are described. In this structure, the wound body includes an active portion in which electrode films in the pair of dielectric films overlap each other, and the diameter of the active portion is greater than the diameter of each metal-sprayed electrode in the cross section perpendicular to the winding axis of the wound body to reduce the volume ratio of each metal-sprayed electrode. The resultant film capacitor can have a smaller size and larger capacity.
One or more embodiments of the film capacitor element will now be described.
One or more embodiments of the present disclosure will now be described with reference to the drawings. The embodiments described below are mere examples of the present disclosure, and may be modified in various manners without departing from the spirit and scope of the present disclosure.
FIG. 1 is a schematic cross-sectional view of a film capacitor element according to one embodiment of the present disclosure, taken along one plane in a first direction X. A film capacitor element 1 includes a body 20 including multiple dielectric films 2 a and 2 b and film electrodes 6 including electrode films 4 a and 4 b on the surfaces of the dielectric films 2 a and 2 b stacked on one another or wound together. The film capacitor element 1 also includes a pair of external electrodes 3 a and 3 b on both ends of the body 20 in the first direction X connected to the electrode films 4 a and 4 b in the multiple film electrodes 6 to form a capacitance portion 20 c (active portion). The capacitance portion 20 c is at the middle between the ends of the body 20 in the first direction X. The body 20 has spaces S between the film electrodes 6. In other words, the dielectric films 2 a and 2 b are plastically deformed with the spaces S in the stacking direction. The width of each space S, or specifically, the distance in the stacking direction between adjacent film electrodes 6 across the space S, is, for example, at least 0.5 μm. The width of each space S may be, for example, one or more times the thickness of the dielectric film 2 a or 2 b, or two or more times the thickness of the dielectric film 2 a or 2 b. Each film electrode 6 has multiple microscopic recesses 7 on its surface.
Each recess 7 may be replaced by a hole that is circular, oval, polygonal, or star-shaped in a plan view, or a groove that is linear, arc-shaped, or dendritic in a plan view. Each recess 7 may also be replaced by two or more holes or grooves connected together. The depth of each recess 7 may be, for example, 10 nm or greater and less than or equal to half the thickness of the dielectric film 2 a or 2 b. For each recess 7 being replaced by a hole, the diameter of the recess 7 in a plan view may be, for example, from 10 nm to 2 μm inclusive. For each recess 7 being replaced by a groove, the width of the recess 7 in a plan view may be, for example, from 10 nm to 2 μm inclusive, and the length may be, for example, 200 μm or less. The density of the recesses 7 may be, for example, 1 to 1000 recesses/mm2 or less.
The recesses 7 have the ratio of the diameter to the depth of the hole (diameter/depth) or the ratio of the width to the depth of the groove (width/depth) being 3 or less.
The dielectric film 2 a or 2 b may be simply referred to as the dielectric film 2. The electrode film 4 a or 4 b may be simply referred to as the electrode film 4.
The film capacitor element 1 may be fabricated with the procedure described below. The dielectric film 2 is prepared first. The dielectric film 2 is obtained by, for example, preparing a resin solution by dissolving an insulating resin in a solvent, applying the resin solution on the surface of a base film of, for example, polyethylene terephthalate (PET) in a sheet, and drying the sheet to volatilize the solvent. The sheet may be applied with a method selected as appropriate from known film deposition methods including doctor blading, die coating, and knife coating. Examples of the solvent used for the sheet include methanol, isopropanol, n-butanol, ethylene glycol, ethylene glycol monopropyl ether, methyl ethyl ketone, methyl isobutyl ketone, xylene, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, dimethylacetamide, cyclohexane, and an organic solvent containing a mixture of two or more solvents selected from the above solvents. The dielectric film 2 can also be formed by stretching a film of resin formed by melt extrusion.
The dielectric film 2 may have the thickness of, for example, 5 μm or less, or specifically the thickness of 0.5 to 2 μm.
Examples of the insulating resin for the dielectric film 2 include polypropylene (PP), PET, polyphenylene sulfide (PPS), polyethylene naphthalate (PEN), polyarylate (PAR), polyphenylene ether (PPE), polyetherimide (PEI), and cycloolefin polymers (COPs). The insulating resin may specifically be COPs having a high insulation breakdown voltage.
The dielectric film 2 may contain the insulating resin selected from the above examples alone or may include other materials. The materials that may be included in the dielectric film 2 other than the resin include, for example, the above organic solvent and an inorganic filler. Examples of the inorganic filler include an inorganic oxide such as alumina, titanium oxide, or silicon dioxide, an inorganic nitride such as silicon nitride, and glass. In particular, a material with a high relative dielectric constant such as a composite oxide having a perovskite structure may be used as an inorganic filler. In this case, the dielectric film 2 has a higher relative dielectric constant across the film. The film capacitor using this dielectric film 2 can have a smaller size. The inorganic filler may be surface-treated by, for example, silane coupling treatment or titanate coupling treatment.
FIG. 2A is a diagram describing a procedure for expanding air and other gases remaining in the film electrodes 6. In FIG. 2A, the electrode films 4 are eliminated for ease of illustration. The film capacitor element 1 including the film electrodes 6 with the multiple microscopic recesses 7 being stacked may be, for example, heated to expand air remaining in the microscopic recesses 7. The expanded air enters between the film electrodes 6, forming the spaces S between the film electrodes 6. The dielectric film 2 is plastically deformed with the spaces S being formed. When the film capacitor element 1 is cooled, the spaces S remain between the film electrodes 6.
In some embodiments, the film capacitor element 1 including the film electrodes 6 with the multiple microscopic recesses 7 being stacked may be accommodated in a container, and the container accommodating the film capacitor element 1 may be evacuated to expand the air in the microscopic recesses 7 on the film electrode 6. The expanded air enters between the film electrodes 6, forming the spaces S between the film electrodes 6. The dielectric film 2 is plastically deformed with the spaces S being formed. When the container accommodating the film capacitor element 1 is under the atmospheric pressure, the spaces S remain between the film electrodes 6.
In some embodiments, the film capacitor element 1 including the film electrodes 6 with the multiple microscopic recesses 7 being stacked may be accommodated in a container. The container accommodating the film capacitor element 1 may be evacuated, and the film capacitor element 1 may be heated to expand the air in the recesses 7 on the film electrode 6 more easily.
FIG. 2B is a diagram describing a procedure for vaporizing a solvent remaining in the film electrodes 6. In FIG. 2B, the electrode films 4 are eliminated for ease of illustration. The film capacitor element 1 including the film electrodes 6 being stacked may be, for example, heated to vaporize the solvent remaining between the film electrodes 6. The vaporized solvent enters between the film electrodes 6 to form the spaces S between the film electrodes 6. The dielectric film 2 is plastically deformed with the spaces S being formed. When the film capacitor element 1 is cooled, the spaces S remain between the film electrodes 6.
FIG. 3 is a diagram of the film capacitor element 1 encapsulated with a resin. Lmax−1m is the maximum thickness difference, and (Lmax−1m)/1m×100 is the maximum expansion rate (%) in the stacking direction, where Lmax is the dimension of the expanded body 20 in the stacking direction, and 1m is the dimension of the external electrode 3 a or 3 b in the stacking direction. The maximum thickness difference and the maximum expansion rate in the stacking direction are both greater than 0. The maximum thickness difference may be, for example, greater than or equal to the thickness of the dielectric film 2 or greater than or equal to 0.5 μm. The maximum expansion rate in the stacking direction may be 100% or less, 50% or less, or specifically 25% or less. Terminals 5 are connected to the external electrodes 3 a and 3 b.
FIG. 4 is a schematic diagram describing the pressure from the resin encapsulation applied to the film capacitor element 1. The dielectric film 2 in each layer is plastically deformed with the capacitance portion 20 c between the pair of external electrodes 3 a and 3 b expanding in the stacking direction and the spaces S between the film electrodes 6 in the layers. The pressure applied to the capacitance portion 20 c in the stacking direction is reduced with air or other gases in the spaces S between the film electrodes 6 in the layers. The gases in the spaces S may flow from gaps around the external electrodes 3 a and 3 b into the spaces S in the other layers. This further reduces the pressure applied to the capacitance portion 20 c.
This structure reduces the likelihood of high pressure being applied to the capacitance portion 20 c in the stacking direction and reduces thermal damage to the film electrodes 6 due to contact between the film electrodes 6 under high pressure and thus reduces breaks from any short circuit.
The spaces S may be formed at least partially in the stacking direction of the body 20. The spaces S may extend over both ends of the body 20 in the first direction X, or may extend partially between the two ends.
FIG. 5 is a schematic cross-sectional view of a film capacitor according to one embodiment. A film capacitor 100 includes the film capacitor element 1 according to the above embodiment, a housing 10 accommodating the film capacitor element 1, and a sealant 9 sealing the film capacitor element 1 accommodated in the housing 10. The sealant 9 is, for example, a resin. The film capacitor 100 can be less susceptible to breaks due to a short circuit and is highly reliable. The film capacitor element is not limited to the film capacitor element 1 described in FIGS. 1 to 4 , but may be any other film capacitor element.
In another embodiment, the electrode films 4 a and 4 b and the dielectric films 2 a and 2 b without being joined together may be stacked on one another or wound together, without the electrode films 4 a and 4 b being formed on the dielectric films 2 a and 2 b. In some embodiments, the film electrode 6 including the dielectric film 2 a with an electrode film 4 a on one surface of the dielectric film 2 a and an electrode film 4 b on the other surface of the dielectric film 2 a, and the dielectric film 2 b with no electrode films 4 a and 4 b may be stacked on one another or wound together.
The present disclosure may be implemented in the following forms.
A film capacitor element according to one aspect of the present disclosure includes a body including a plurality of dielectric films, a plurality of first electrode films, and a plurality of second electrode films being stacked on one another or being wound together, a first external electrode at one end of the body and electrically connected to the plurality of first electrode films, and a second external electrode at another end of the body and electrically connected to the plurality of second electrode films. The body includes a capacitance portion in which each of the plurality of first electrode films faces a corresponding second electrode film of the plurality of second electrode films with a corresponding dielectric film of the plurality of dielectric films in between, and the capacitance portion includes spaces each between a corresponding dielectric film of the plurality of dielectric films and a corresponding first electrode film of the plurality of first electrode films or between a corresponding dielectric film of the plurality of dielectric films and a corresponding second electrode film of the plurality of second electrode films.
A film capacitor according to one aspect of the present disclosure includes the film capacitor element, a housing accommodating the film capacitor element, and a sealant sealing the film capacitor element accommodated in the housing.
The film capacitor element and the film capacitor according to the embodiments of the present disclosure can reduce breaks due to a short circuit and are highly reliable.
Although the embodiments of the present disclosure have been described in detail, the present disclosure is not limited to the above embodiments, and may be modified or changed variously without departing from the spirit and scope of the present disclosure. The components described in the above embodiments may be entirely or partially combined as appropriate unless any contradiction arises.
REFERENCE SIGNS LIST
    • 100 film capacitor
    • 1 film capacitor element
    • 2 a, 2 b dielectric film
    • 3 a, 3 b external electrode
    • 4 a, 4 b electrode film
    • 20 body
    • 20 c capacitance portion
    • 6 film electrode
    • 9 sealant
    • S space

Claims (4)

The invention claimed is:
1. A film capacitor element, comprising:
a body including a plurality of dielectric films, a plurality of first electrode films, and a plurality of second electrode films being stacked on one another or being wound together;
a first external electrode at one end of the body and electrically connected to the plurality of first electrode films; and
a second external electrode at another end of the body and electrically connected to the plurality of second electrode films,
wherein the body includes a capacitance portion in which each of the plurality of first electrode films faces a corresponding second electrode film of the plurality of second electrode films with a corresponding dielectric film of the plurality of dielectric films in between,
the capacitance portion includes spaces each between a corresponding dielectric film of the plurality of dielectric films and a corresponding first electrode film of the plurality of first electrode films or between a corresponding dielectric film of the plurality of dielectric films and a corresponding second electrode film of the plurality of second electrode films, and
wherein a maximum thickness difference Lmax−1m is greater than or equal to the thickness of the dielectric film, wherein Lmax is the dimension of the body in a stacking direction and 1m is the dimension of the first external electrode or the second external electrode in the stacking direction.
2. The film capacitor element according to claim 1, further comprising:
a plurality of film electrodes each including, on a surface of each of the plurality of dielectric films, a first electrode film of the plurality of first electrode films or a second electrode film of the plurality of the second electrode films,
wherein a surface of each of the plurality of film electrodes has a plurality of microscopic recesses, wherein a depth of each recess is 10 nm or greater and less than or equal to half of the thickness of the dielectric film.
3. The film capacitor element according to claim 1, wherein
each space has a width in a stacking direction of the films being greater than or equal to a thickness of each of the plurality of dielectric films.
4. A film capacitor, comprising:
the film capacitor element according to claim 1;
a housing accommodating the film capacitor element; and
a sealant sealing the film capacitor element accommodated in the housing.
US17/785,258 2019-12-20 2020-12-09 Film capacitor element and film capacitor Active 2041-04-25 US12062499B2 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP2019230984 2019-12-20
JP2019-230984 2019-12-20
PCT/JP2020/045815 WO2021125006A1 (en) 2019-12-20 2020-12-09 Film capacitor element and film capacitor

Publications (2)

Publication Number Publication Date
US20230021057A1 US20230021057A1 (en) 2023-01-19
US12062499B2 true US12062499B2 (en) 2024-08-13

Family

ID=76476590

Family Applications (1)

Application Number Title Priority Date Filing Date
US17/785,258 Active 2041-04-25 US12062499B2 (en) 2019-12-20 2020-12-09 Film capacitor element and film capacitor

Country Status (5)

Country Link
US (1) US12062499B2 (en)
EP (1) EP4080530A4 (en)
JP (1) JP7666834B2 (en)
CN (1) CN114868215B (en)
WO (1) WO2021125006A1 (en)

Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3253199A (en) * 1963-01-29 1966-05-24 Sprague Electric Co Capacitors having porous material to aid impregnation
JPS5193358A (en) 1975-02-14 1976-08-16
WO2000008661A1 (en) 1998-08-07 2000-02-17 Abb Research Limited Improvements in or relating to electronic components
JP2015070165A (en) 2013-09-30 2015-04-13 京セラ株式会社 Laminate and film capacitor
JP2015101677A (en) * 2013-11-26 2015-06-04 京セラ株式会社 Dielectric film, and film capacitor
DE102014202067A1 (en) 2014-02-05 2015-08-06 Siemens Aktiengesellschaft film capacitor
JP2015211071A (en) 2014-04-24 2015-11-24 京セラ株式会社 Film capacitor
US20160126016A1 (en) * 2014-10-28 2016-05-05 Toyota Jidosha Kabushiki Kaisha Film capacitor
JP2016219752A (en) 2015-05-26 2016-12-22 小島プレス工業株式会社 Laminated film capacitor
US20180090277A1 (en) * 2015-03-26 2018-03-29 Kyocera Corporation Film capacitor, combination type capacitor, inverter, and electric vehicle
US20210358693A1 (en) * 2019-02-07 2021-11-18 Murata Manufacturing Co., Ltd. Film capacitor
US20220102072A1 (en) * 2019-07-10 2022-03-31 Murata Manufacturing Co., Ltd. Film capacitor and film for film capacitor

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58109237U (en) * 1982-12-15 1983-07-25 ニチコン株式会社 plastic film capacitor
FR2684796A1 (en) * 1991-12-10 1993-06-11 Europ Composants Electron METAL DIELECTRIC FILM CAPACITOR AND METHOD FOR PRODUCING SUCH CAPACITOR.
KR960000953B1 (en) * 1992-12-10 1996-01-15 삼성전자주식회사 Semiconductor memory device and the manufacturing method
JP2893568B2 (en) * 1993-12-30 1999-05-24 岡谷電機産業株式会社 Manufacturing method of capacitor
JPH0897081A (en) * 1994-09-21 1996-04-12 Matsushita Electric Ind Co Ltd Method of manufacturing film capacitor
US6954349B2 (en) * 2001-06-08 2005-10-11 Matsushita Electric Industrial Co., Ltd. Metallized film capacitor
JP5439944B2 (en) * 2009-05-18 2014-03-12 株式会社村田製作所 Multilayer electronic component and manufacturing method thereof
JP7193070B2 (en) * 2018-02-05 2022-12-20 株式会社指月電機製作所 Film capacitor

Patent Citations (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3253199A (en) * 1963-01-29 1966-05-24 Sprague Electric Co Capacitors having porous material to aid impregnation
JPS5193358A (en) 1975-02-14 1976-08-16
WO2000008661A1 (en) 1998-08-07 2000-02-17 Abb Research Limited Improvements in or relating to electronic components
US6407905B1 (en) 1998-08-07 2002-06-18 Abb Corporate Research Ltd. Electronic components
JP2015070165A (en) 2013-09-30 2015-04-13 京セラ株式会社 Laminate and film capacitor
JP2015101677A (en) * 2013-11-26 2015-06-04 京セラ株式会社 Dielectric film, and film capacitor
DE102014202067A1 (en) 2014-02-05 2015-08-06 Siemens Aktiengesellschaft film capacitor
CN204760235U (en) 2014-02-05 2015-11-11 西门子公司 Film capacitor
JP2015211071A (en) 2014-04-24 2015-11-24 京セラ株式会社 Film capacitor
US20160126016A1 (en) * 2014-10-28 2016-05-05 Toyota Jidosha Kabushiki Kaisha Film capacitor
US20180090277A1 (en) * 2015-03-26 2018-03-29 Kyocera Corporation Film capacitor, combination type capacitor, inverter, and electric vehicle
JP2016219752A (en) 2015-05-26 2016-12-22 小島プレス工業株式会社 Laminated film capacitor
US20210358693A1 (en) * 2019-02-07 2021-11-18 Murata Manufacturing Co., Ltd. Film capacitor
US20220102072A1 (en) * 2019-07-10 2022-03-31 Murata Manufacturing Co., Ltd. Film capacitor and film for film capacitor

Also Published As

Publication number Publication date
EP4080530A4 (en) 2024-01-03
JP7666834B2 (en) 2025-04-22
CN114868215A (en) 2022-08-05
US20230021057A1 (en) 2023-01-19
CN114868215B (en) 2024-08-20
WO2021125006A1 (en) 2021-06-24
EP4080530A1 (en) 2022-10-26
JPWO2021125006A1 (en) 2021-06-24

Similar Documents

Publication Publication Date Title
KR20140138701A (en) Micro -and nanoscale capacitors that incorporate an array of conductive elements having elongated bodies
CN104040656B (en) Thin film capacitor
US10726995B2 (en) Dielectric structures for electrical insulation with vacuum or gas
JP7193070B2 (en) Film capacitor
CN111279445A (en) Film capacitors, junction capacitors, inverters using the same, and electric vehicles
CN111213217A (en) Film capacitor, connection type capacitor, inverter using the same, and electric vehicle
US12362104B2 (en) Capacitor
US12062499B2 (en) Film capacitor element and film capacitor
CN112912980B (en) Film capacitor with acrylic dielectric layer inside
JP2014107394A (en) Metalized film capacitor
CN114041263B (en) Multilayer capacitors, link capacitors, inverters, and electric vehicles
JP2015103700A (en) Film capacitor
JP6339344B2 (en) Film capacitor
JP6441585B2 (en) Film capacitor
US11854750B2 (en) Electrolyte capacitor comprising isolated edges
KR102815854B1 (en) Hybrid metal film forming method for film capacitors
CN114746265B (en) Metallized film and film capacitor using the same
JP2000357623A (en) Metallized capacitors
JP2016046291A (en) Film capacitor element and method for manufacturing the same
JPH07130215A (en) Compound dielectric film and capacitor
JP2004087653A (en) Metallized film capacitors
HK40053055A (en) Film capacitor with coated acrylic dielectric layer inside
HK40053055B (en) Film capacitor with coated acrylic dielectric layer inside
JP2900751B2 (en) Film capacitor and manufacturing method thereof
JP2021190664A (en) How to make a film capacitor

Legal Events

Date Code Title Description
AS Assignment

Owner name: KYOCERA CORPORATION, JAPAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:SENOO, YUKI;REEL/FRAME:060195/0874

Effective date: 20201211

FEPP Fee payment procedure

Free format text: ENTITY STATUS SET TO UNDISCOUNTED (ORIGINAL EVENT CODE: BIG.); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

STPP Information on status: patent application and granting procedure in general

Free format text: DOCKETED NEW CASE - READY FOR EXAMINATION

STPP Information on status: patent application and granting procedure in general

Free format text: NON FINAL ACTION MAILED

STPP Information on status: patent application and granting procedure in general

Free format text: RESPONSE TO NON-FINAL OFFICE ACTION ENTERED AND FORWARDED TO EXAMINER

STPP Information on status: patent application and granting procedure in general

Free format text: NOTICE OF ALLOWANCE MAILED -- APPLICATION RECEIVED IN OFFICE OF PUBLICATIONS

ZAAA Notice of allowance and fees due

Free format text: ORIGINAL CODE: NOA

ZAAB Notice of allowance mailed

Free format text: ORIGINAL CODE: MN/=.

STPP Information on status: patent application and granting procedure in general

Free format text: PUBLICATIONS -- ISSUE FEE PAYMENT VERIFIED

STCF Information on status: patent grant

Free format text: PATENTED CASE